Satsuma Rebellion - Wikipedia

On September 24, 1877, the Battle of Shiroyama was the decisive victory of the Imperial Japanese Army over the Satsuma Rebellion. From the article:

"Although Satsuma had been one of the key players in the Meiji Restoration and the Boshin War, and although many men from Satsuma had risen to influential positions in the new Meiji government, there was growing dissatisfaction with the direction the country was taking. The modernization of the country meant the abolition of the privileged social status of the samurai class, and had undermined their financial position. The very rapid and massive changes to Japanese culture, language, dress and society appeared to many samurai to be a betrayal of the jōi ("expel the barbarian") portion of the sonnō jōi justification used to overthrow the former Tokugawa shogunate.

Saigō Takamori, one of the senior Satsuma leaders in the Meiji government who had supported the reforms in the beginning, was especially concerned about growing political corruption (the slogan of his rebel movement was shinsei-kōtoku (新政厚徳, new government, high morality). Saigō was a strong proponent of war with Korea in the Seikanron debate of 1873. At one point, he offered to visit Korea in person and to provoke a casus belli by behaving in such an insulting manner that the Koreans would be forced to kill him. Saigō expected both that a war would ultimately be successful for Japan and also that the initial stages of it would offer a means by which the samurai whose cause he championed could find meaningful and beneficial death. When the plan was rejected, Saigō resigned from all of his government positions in protest and returned to his hometown of Kagoshima, as did many other Satsuma ex-samurai in the military and police forces.

To help support and employ these men, in 1874 Saigō established a private academy in Kagoshima. Soon 132 branches were established all over the prefecture. The “training” provided was not purely academic: although the Chinese classics were taught, all students were required to take part in weapons training and instruction in tactics. Saigō also started an artillery school. The schools resembled paramilitary political organizations more than anything else, and they enjoyed the support of the governor of Satsuma, who appointed disaffected samurai to political offices, where they came to dominate the Kagoshima government. Support for Saigō was so strong that Satsuma had effectively seceded from the central government by the end of 1876.[3]"